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Crate Engine Builder Kit by Butler, 406-412 cu. in. Ready to Assemble


  • Butler Performance Stealth/Stock Appearing Engine 390-425hp
  • 3.75" Stroke 400 block
  • Depending on core availability- 4.150, 4.155, 4.160, 4.181 Bore
  • Cast or Forged Crank/ Forged Rods
  • Custom machined and ready to assemble
  • All blocks undergo the "Butler Process"
  • Builder Kits are shipped unassembled. Must be assembled by you or your shop

Availability: Due to Popular Demand current lead time runs about 12-14 weeks Fully insured shipping will be quoted. (Usually $500-700 on average). Additional fees for residential and liftgate.
Pricing: $12,495.00

Customize Your Item

- Choose Your Block -
 * required
- Choose Your Crank -
 * required
- Choose Your Rods -
 * required
- Choose Your Heads -
 * required
- Choose Your Ignition -
 * required
- Choose Your Induction -
 * required
- Choose Your Block Color -
 * required
- Choose Main Cap Upgrade -
 * required
- Choose Your Oil Pump -
 * required
- Choose Your Oil Pan -
 * required
- Choose Your Cam Idle Quality -
 * required
- Choose Your Lifters -
 * required
- Choose Your Rockers -
 * required
- Choose Your Stealth Option -
 * required
- Choose Your Valve Covers -
 * required
- Choose Balancer -
 * required
- Choose Your Flexplate/Flywheel -
 * required


406-412cu. in.
Starting at 390-425 HP


  • 400 Block With Main Studs, Dip Stick
  • Cast or Forged Crank
  • Eagle Forged Rods
  • BP Forged Pistons and Pins
  • Total Seal Rings
  • C77 Race Bearings
  • BP Billet Gears and Chains
  • High Volume Oil Pump
  • BP/COMP Hyd Roller Cam
  • Hyd Roller Lifters
  • BP Custom Pushrods 5/16 .116" Wall
  • Harmonic Damper
  • Roller Rockers
  • Edelbrock Out of Box or BP Built Edelbrock Heads
  • Carb or EFI of your choice
  • Stock Type or Canton Oil Pan & Pickup
  • Port Matched Intake
  • TPP Valley Pan
  • Flowkooler Water Pump
  • New 11 Bolt Timing Cover, Plates, and Sleeves
  • Ignition Kit
  • IMI Starter
  • Engine Paint and Valve Cover Options
  • All gaskets and stainless steel accessory and ARP fasteners

The Block

We start with the exact same blocks you would build on your own. It's what we do to take these old dirty blocks that you see here to a beautiful custom built Butler engine. It takes many critical steps in order to become the proper foundation to be a custom Butler Performance engine.

Step 1- 3 Step Cleaning Process

-Baked, Blasted, and Cleaned

Step 2- Visually Inspected

Step 3- Magnafluxed/Sonic Tested

Step 4- Replace Dowel Pins

Step 5- Align Bored (if required)/ Align Honed

Step 6- Bored and Honed with a Torque Plate

***Due to the fact that these 40 plus year old blocks cleanup of cylinders varies on a block to block basis. Therefore your final bore size will be determined at this step. Sufficient wall thickness will be verified once again regardless of final bore size. We will select the smallest bore available for your particular block unless you request a larger bore size/larger cu.in.***

Step 7- Square Decked

Step 8- Deburred/ Final Multi Prep Process

 (It takes over a full days work for the final prepping process. Including tapping all bolt holes and cleaning all oil galleys)

Step 9- Final Jet Wash/Cleaning/Wipe Down

Step 10- Ready for Assembly

557 Block

400 blocks with 557 castings are great blocks but the main areas were thinner than the standard casting 400's. This is not an issue whatsoever as long as you don't over stroke (4.00 str max) it or exceed the recommended hp levels (450hp). Otherwise these are great for strong economical street engines builds.

All rotating assemblies sold by Butler Performance, regardless of brand, are neutrally balanced in our shop by our experienced machinists.

Images show assembled with optional parts. Contact us for detailed quote for your application and specifications.

Drive, accessory pulleys, and March Serpentine systems sold separately

Air cleaner or drop base sold separately

Don't sweat the details. Once order is places one of the Butler Engine Tech's will contact you to finalize any details related to your specific car, application, and final details. Some of these details will be valve cover logo, breather location, and any other parts needed for your specific application. We will answer any questions you may have and get your build processed and in line for machining. 


  • BP-ENGINE-KIT-406-412
  • BP-ENGINE-KIT-406-412
  • Butler Performance
  • Due to Popular Demand current lead time runs about 12-14 weeks Fully insured shipping will be quoted. (Usually $500-700 on average). Additional fees for residential and liftgate.
  • New

Shipping Information

  • Item Requires Shipping

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